Chelsea's Premier League title defence was nothing short of horrendous and they ended the campaign in 10th place.
Jose Mourinho paid the price for Chelsea's dismal start to the season by being sacked in December, before Guus Hiddink steadied the ship and staved off any threat of relegation.
Conte will take over at Stamford Bridge after leading Italy at Euro 2016, and Gallas - who won two Premier League titles with Chelsea during his stay between 2001 and 2006 - expects the former Juventus boss to propel the club back towards the top of the table.
The former France defender told Omnisport: "It was very, very hard to see Chelsea in this position, especially since I spent five years there.
"But it can happen, it can happen to the greatest clubs. I think next season will be another season. I hope that we will see Chelsea at the top.
"I knew it was not easy for them but seen from the outside, it was difficult to accept this situation. As I said, every season is different. Next season will be a new season for Chelsea.
"I think he [Conte] will bring his experience. He is a coach who likes to win competitions. He was able to prove it with Juve. I think he will bring a lot of rigour to this team of Chelsea."